Characterization and seed transmission of Hosta virus X isolated from Hosta plants.

摘要

A Potexvirus was isolated from diseased hosta (Hosta longipes) plants causing mosaic, mottle interveinal chlorosis symptoms between secondary veins, and leaf desiccation. The virus was identified as Hosta virus X (HVX-Kr) based on its biological, serological and molecular properties. The infection rate of HVX in cultivated hostas was 48.4%, and 21 of the 43 samples contained HVX. The virus was detected from seeds, and sprouts and seedlings. HVX was seed-transmitted on hosta cv. Blue Cadet. More than 7.5% of the seeds from HVX-infected hosta were HVX-contaminated. The coat protein gene of HVX-U was amplified by RT-PCR and its nucleotide sequence was determined. The CPs of HVX-Kr and HVX-U were highly identical with regard to their amino acid (100.0%) and nucleotide (98.9%) sequences. The sequences of the CP gene varied among the isolates obtained from different hostas. Total nucleic acids extracted from the leaf of virus-infected hostas were used for the detection of HVX by RT-PCR using HVX-specific primers (HV UP:5722-5742 bp region of HVX-Kr strain/HV DN: 6428-6448 bp region of HVX-Kr strain). The overall similarity of the coat proteins with other HVX isolates varied from 98.3 to 99.7% at the nucleotide level, and from 98.2 to 100.0% at the amino acid level. This is the first report of molecular evidence supporting HVX as a distinct species of the genus Potexvirus and seed transmission of HVX..